The trowel used by the Duke of Edinburgh to lay the foundation-stone of the fourth Eddystone lighthouse in August 1879. The fourth lighthouse to be located on Eddystone Rocks, 14 miles off the coast of Plymouth in Devon, was designed and built by Sir James Nicholas Douglas (1826-1898). Begun in 1879, Douglas's lighthouse incorporated new electric lights capable of being seen for almost 18 nautical miles; over three miles further than the tallow candle lantern of the previous lighthouse. This meant that the Eddystone signal overlapped the signal from the lighthouse at Lizard Point in Cornwall, providing for the first time a safe pasage along this coastline.
© Science Museum / Science & Society Picture Library